1. Field of the Invention
The invention relates to a saw blade for medical, particularly surgical applications, having a receiver for accommodating a saw which applies a sawing motion, especially an oscillating sawing motion, to the saw blade.
2. Discussion of Related Art
Particularly in the area of knee surgery, is it necessary to cut the knee or knee sections and other tissue, such as cartilage or the like, by means of a saw when an artificial knee joint is implanted. To do this, compressed air-driven or electrical saws (often battery-driven devices) are known which have a saw blade as is shown in FIG. 1.
The saw blade (1) is made as a thin sheet and, therefore, has a flat structure. On one end, it has a sawtooth profile (2) which cuts the bone. The saw blade (1) is held in the saw by means of a receiver (3), for example, with a multitooth profile. The saw applies a sawing motion to the saw blade. In this case, the saw turns the saw blade back and forth by a small angle around the axis of the receiver (3), causing the sawtooth profile (2) to move in an oscillating manner. In doing so, the saw applies to the saw blade (1) such large angular movements on the receiver (3) that the lifting motion of the sawtooth profile (2) is only a few millimeters. The sawing frequency generally varies on the order of roughly 250 Hz.
Generic saw blades are known from U.S. Pat. No. 4,036,236 and EP 0695 607 A1. The saw blades described by those documents provide ribs or grooves which run linearly from the receiver 3 as far as the sawtooth profile 2 for purpose of stiffening or for reducing the weight of the saw blade.
However, when bones are being cut in the knee area what is important is making a cut as exact as possible. The required precision varies less than a millimeter, and known saw blades engender problems in this respect.
The known saw blade, during sawing, must oscillate with such a high frequency that the dynamic forces cause vibration of the saw blade in the direction normal to the flat area of the saw blade. In the resonant area, the vibration amplitude can become so large that in spite of the use of templates, which exactly guide the saw, the required sawing precision cannot be maintained. The cut becomes inexact which results in the corresponding consequences in surgery.
Another disadvantage is caused by the fact that the saw being used is exposed to high dynamic stress so that its bearings are subject to high loads and wear. In the saws which are conventionally used, it is necessary to often replace their bearings so that sufficient accuracy can be achieved.
Reducing the thickness of the saw blade does not yield any overall benefit, since the dynamic effect as a result of the reduced mass of the saw blade is less, but deflection of the blade is increased when working forces are applied.